What’s the difference between 2D, Doppler, 3D and 4D ultrasounds?

For 2D Ultrasound, transducer is placed on your belly or into your vagina to send sound waves through your body. The waves bounce off internal organs and fluids, and a computer converts these echoes into a two-dimensional image (or a cross-sectional view) of the fetus on a screen.

Difference between 2D, Doppler, 3D and 4D ultrasounds

With Doppler fetal ultrasound, your practitioner uses a hand-held ultrasound device to amplify the sound of the fetal heartbeat with the help of a special jelly on your belly.

For 3D ultrasounds, multiple two-dimensional images are taken at various angles and then pieced together to form a three-dimensional rendering. For instance, instead of just seeing a profile view of your cutie’s face, in a 3D sonogram, you can see the whole surface (it looks more like a regular photo).

A 4D ultrasound is similar to a 3D ultrasound, but the image shows movement. That means like a video, in a 4D sonogram you see your baby doing things in real-time (like opening and closing his eyes and sucking his thumb).

The safety of 3D and 4D ultrasounds during pregnancy

1. Early Pregnancy scan

Ita also called Fetal Viability Scan.A Fetal Viability Scan is an ultrasound examination, usually carried out at 7 to 12 weeks, to confirm that the pregnancy is developing normally and to provide reassurance.

This Scan provide following details

Location of Pregnancy (Intrauterine / Ectopic)
Gestational age estimation
Viability
No.of the fetus (Single / Twin)
Uterine Pathology
Details of adnexa

It is mostly done by Transvaginal route because its gives clear view of Uterus and fetus.

2. First Trimester Scan

It is done at around 11 to 13 week of gestational age.

This scan provide following details

Detection of early anomaly
Prediction of Pre eclampsia
Prediction of Preterm Labour by cervical length
Aneuploidy screening by measuring Nuchal Translucency,Nasal bone,Tricuspid Regurgitation,Ductus Venosus Doppler.

A good first trimester scan has a 90% sensitivity of aneuploidy screening.To increase the sensitivity of Aneuploidy screening Double marker of NIPT done in which mother blood is taken.These test will give additional 9% of sensitivity.

For confirmation of aneuploidy Invasive test like Amniocentesis or Chorionic Villous Biopsy is done.

3. TIFFA 2 Scan

It is called Targeted Imaging For Fetal Anomalies.During second trimester one of important and vital Ultrasound scan is TIFFA 2 scan.

This is usually done at 20 to 22 weeks.

It is done to check fetal growth,development and fetal physical abnormalities.

The anomaly scan or the TIFFA scan examines the fetus from head to toe monitoring the overall growth, development, and health. The sonographer checks the baby’s anatomy and examines any structural problem from head to toe. The scan can measure the size and weight of the fetus. It also looks at the position of your placenta, the umbilical cord, and amniotic fluid around the fetus. Any abnormal positioning of the placenta might result in miscarriages or heavy bleeding during pregnancy and can cause many complications to the mother and the baby.

4. Growth and Doppler Scan

During pregnancy, there are 2 scans that (generally) everyone will have: the 10 to 12-week dating scan and the 20-week abnormality scan.

If you have a scan during your 3rd trimester, it’s called a ‘growth scan’ or ‘wellbeing scan’ – which is done to take your baby’s measurements, and assess their health.

These growth scans usually take place in the 3rd trimester of pregnancy. That’s why you might’ve heard them called ‘3rd trimester scans’. Usually, it’ll be after 28 weeks.

They’ll only be scheduled in if doctors want to be reassured that any symptoms, concerns about baby’s movements or risk factors aren’t affecting your baby’s health.

During a standard growth scan, there are 4 or 5 things that will be looked of :-

your baby’s abdominal circumference
your baby’s head circumference
how long your baby’s femur (thigh bone) is
the fluid surrounding your baby
if needed, the blood flow in the umbilical cord
Location of Placenta
Doppler of vessels
Anomaly screening

If you need other checks, they’ll be done during the scan, too.

This info is then compared to how far along you are in your pregnancy, and is then used to estimate your baby’s weight.

They’ll also be able to tell you if everything’s OK with the baby, and everything else: the fluid, the cord, and the placenta, etc.